Furuno SS542 Instruction Manual

D-17-621-02-rev.2 17-621-02-rev.2 01/29/19
WARNING
Installation of the anti-rotation bolt is mandatory!
The anti-rotation bolt holds the fairing firmly in place. Failure to install the anti-
rotation bolt may result in the fairing rotating while the boat is underway. The
effect may be violent movement and loss of steering. This could result in serious
injury or death to passengers and/or damage to the boat or other property.
Thru-Hull Mount
Multi-beam Sonar & Depth Transducer
with Temperature Sensor & High-Performance Fairing
Model SS542
Applications
• Stainless steel transducer compatible with all hull materials.
Recommended for aluminum hulls to prevent electrolytic corrosion
provided the stainless steel transducer is isolated from the metal hull.
• Maximum deadrise angle of 20°.
Follow the precautions below for optimal product
performance and to reduce the risk of property damage,
personal injury, and/or death.
WARNING: The transducer must be installed with a High-
Performance Fairing.
WARNING: When installing the High-Performance Fairing
carefully follow these installation instructions.
WARNING: Always wear safety glasses, a dust mask, and
ear protection when installing.
WARNING: The fairing must be installed parallel to the keel
to ensure proper boat handling.
WARNING: Do not install a fairing that has been mis-cut.
Replace it.
• Cutting the fairing at an angle greater than the maximum
allowed will cut into the transducer and/or bolt pocket,
thus weakening the fairing.
• Do not allow any gap between the fairing and the hull that is
greater than 3mm (1/8"). When the boat is underway,
water will enter any gaps and push against the fairing with
considerable force, possibly rotating it.
WARNING: Immediately check for leaks when the boat is
placed in the water. Do not leave the boat unchecked for
more than three hours. Even a small leak may allow
considerable water to accumulate.
CAUTION: Stainless steel transducer in a metal hull—
Use sleeving to isolate the stainless steel transducer and
anti-rotation bolt from the metal hull. Failure to do so will
cause electrolytic corrosion.
CAUTION: Never pull, carry, or hold the transducer by the
cables as this may sever internal connections.
CAUTION: Never strike the transducer.
CAUTION: Do not over-tighten the hull nut and the nut on
the anti-rotation bolt, crushing the fairing and/or hull.
CAUTION: The transducer and the yellow triangular plug
must be flush with the fairing for smooth water flow under the
transducer.
CAUTION: Never use solvents. Cleaner, fuel, sealant, paint,
and other products may contain solvents that can damage
plastic parts, especially the transducer’s face.
IMPORTANT:Read the instructions completely before
proceeding with the installation. These instructions
supersede any other instructions in your instrument manual
if they differ.
OWNER’ S GUIDE & INSTALLATION INSTRUCTIONS

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Identify Your Model
The model name is printed on the cable tag.
Tools & Materials
Safety glasses
Dust mask
Ear protection
Electric drill
Drill bits and hole saws
Pilot hole 3mm or 1/8"
Angle finder
Band saw (sharp blade)
Rasp or power tool
Sandpaper
Mild household detergent or weak solvent (such as alcohol)
File (installation in a metal hull)
Marine sealant (suitable for below waterline)
Slip-joint pliers
Mallet
Grommets (some installations)
Cable ties
Water-based anti-fouling paint (mandatory in salt water)
Installation in a cored fiberglass hull (see page 5)
Cylinders, wax, tape, and casting epoxy.
Hull Material Transducer
Hole-Saw Size
Anti-rotation Bolt Hole
Drill Bit Size
solid fiberglass or wood 33mm or 1-5/16" 14mm or 9/16"
metal 35mm or 1-3/8" 15mm or 9/16"
Hole Saw for
Transducer
(outer skin)
Minimum Size
Hole Saw for
Transducer
(inner cored hull)
Drill Bit for
Anti-rotation Bolt
(outer skin)
Minimum Size
Drill Bit for
Anti-rotation Bolt
(inner cored hull)
33mm or 1-5/16" 50mm or 2" 14mm or 9/16" 30mm or 1-1/4"
Mounting Location
CAUTION: Do not mount in line with or near water intake or
discharge openings or behind strakes, struts, fittings, or hull
irregularities that will disturb the water flow.
• The water flowing under the hull must be smooth with a
minimum of bubbles and turbulence (especially at high speeds).
• The transducer’s face must be continuously immersed in water.
• The transducer beam must be unobstructed by the keel or
propeller shaft(s).
• Choose a location away from interference caused by power and
radiation sources such as: the propeller(s) and shaft(s), other
machinery, other echosounders, and other cables. The lower
the noise level, the higher the echosounder gain setting that
can be used.
• Choose a location with a minimum deadrise angle.
• Choose an accessible spot inside the vessel with adequate
space for the height of the stem and tightening the nut.
Boat Types (Figure 1)
•Displacement hull powerboat—Locate 1/3 of the way back
along the LWL and 150–300mm (6–12") off the centerline. The
starboard side of the hull where the propeller blades are moving
downward is preferred.
•Planing hull powerboat—Mount well aft near the centerline and
well inboard of the first set of lifting strakes to insure that it is in
contact with the water at high speeds. The starboard side of the
hull where the propeller blades are moving downward is preferred.
Outboard and I/O—Mount just forward and to the side of the
engine(s).
Inboard—Mount well ahead of the propeller(s) and shaft(s).
Stepped hull—Mount just ahead of the first step.
Boat capable of speeds above 25kn (29MPH)—Review
transducer location and operating results of similar boats before
proceeding.
Figure 1.
pressure waves
1/3 aft
displacement hull
(6-12")
150-300mm
LWL
Best location for the transducer
(Load Waterline Length)
stepped hull
outboard and I/O
planing hulls
Copyright © 2005 Airmar Technology Corp.
inboard
NOTE: fairing must
be flush with housingtransducer face
hull nut
marine sealant
backing block
Figure 1. Deadrise angle and fairing thickness
High-Performance
hull
stem
aft view
isolation sleeve
min. fairing thickness
74mm (2-7/8")
deadrise
angle
slope of hull
parallel to
water surface
Copyright © 2017 Airmar Technology Corp.
transducer
Fairing
(metal)

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Installation
Cored Fiberglass Hull—Follow separate instructions on page 5.
Hole Drilling: Transducer
1. Drill a 3mm or 1/8" pilot hole perpendicular to the waterline from
inside the hull (Figure 2). If there is a rib, strut or other hull irregularity
near the selected mounting location, drill from the outside.
2. Using the appropriate size drill bit or hole saw, cut a hole from
outside the hull. Be sure to hold the drill plumb, so the hole will
be perpendicular to the water surface.
Cutting the High-Performance Fairing
CAUTION: The end of the fairing with the arrows/triangular
recess always points forward toward the bow when installed. Be
sure to orient the fairing on the band saw, so the angle cut
matches the intended side of the hull and not the mirror image.
1. Measure the deadrise angle of the hull at the selected mounting
location using an angle finder (Figure 2). Check to be sure the
angle does not exceed 20°.
2. Tilt the band saw table to the measured angle and secure the
cutting fence (Figure 3). Do not exceed 20°.
3. Place the fairing on the table, so the cutting guide rests against
the fence (Figure 4). The end with the arrows and triangular
recess will be pointing toward you for installation on the
starboard side of the boat or away from you for installation on
the port side.
4. Adjust the cutting fence, so the fairing will be cut in about two equal
parts (Figure 3). The section that will become the fairing must be a
minimum of 74mm (2-7/8") at its thinest dimension (Figure 2).
5. Recheck steps 1 through 4. Then cut the fairing.
6. When the boat is underway, especially at high speeds, water
will enter any gaps and push against the fairing with
considerable force, possibly rotating it. Shape the fairing to the
hull as precisely as possible with a rasp or power tool. If there is
a gap of more than 3mm (1/8"), replace the fairing.
7. Check to be sure the transducer is flush with the fairing. If it is
recessed more than 0.5mm (1/64") inside the fairing, you may
shim the transducer or carefully file/sand the fairing.
8. The remaining section of the fairing with the cutting guide will
be used as the backing block inside the hull. It will provide a
level surface for tightening the nuts.
Hole Drilling: Anti-rotation Bolt
To locate and drill the hole for the anti-rotation bolt, use the fairing
as a guide. This will ensure that the hole is perpendicular to the
waterline and not drilled at the angle of the hull.
Figure 5. Bedding and installing in a solid fiberglass or wood hull
Copyright © 2017 Airmar Technology Corp.
BOW ►
anti-rotation
bolt
nut &
washer
triangular plug
backing
block
High-
surface facing
outward
hull
hull nut
stem
Performance
Fairing
NOTE: Be sure
the arrow on the
transducer
points forward
toward the bow.
with curved
SS542
Figure 3. Cutting the High-Performance Fairing
deadrise
angle
cutting
guide band saw
table
triangular recess
for installation
on starboard side
fence
Copyright © 2005 - 2010 Airmar Technology Corp.
of the hull
end with arrows and
Figure 4. High-Performance Fairing
Copyright © 2017 Airmar Technology Corp.
triangular
cutting
recess for
anti-rotation bolt
guide
marine sealant on following (shown in red):
- transducer, extending above hull nut 1/4" (NOT surface that will touch water)
- backing block that contacts hull
- hull nut that contacts backing block
- anti-rotation washer that contacts backing block
- yellow triangular plug: fill hollow half way (NOT curved surface that will touch water)
- anti-rotation bolt including bolt head, extending above nut 1/4"
- fairing that contacts hull

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1. Dry fit the transducer in the fairing. Thread the cables through
the large hole in the fairing and through the mounting hole in the
hull. Seat the transducer firmly within the recess in the fairing
(Figure 5 or 6). Be sure the arrow on the transducer points
toward the triangular recess in the fairing.
2. Slide the transducer with the fairing in place into the mounting
hole. Using the bolt hole in the fairing as your guide, drill a 3mm
(1/8”) pilot hole through the hull for the anti-rotation bolt.
3. Using the appropriate size drill bit, hold the fairing in place and
drill a hole for the anti-rotation bolt.
4. Remove the assembly and cables from the mounting hole.
5. Sand and clean the area around both holes, inside and outside,
to ensure that the sealant will adhere properly to the hull. If
there is any petroleum residue inside the hull, remove it with
either mild household detergent or a weak solvent such as
alcohol before sanding.
Metal hull—Remove all burrs with a file and sandpaper.
Bedding the Transducer
CAUTION: Be sure the surfaces to be bedded are clean and dry.
1. Remove the transducer from the fairing.
2. Apply a 2mm (1/16") thick layer of marine sealant to the surface
of the transducer that will contact the fairing and up the stem
(Figure 5 areas in red). The sealant must extend 6mm
(1/4") higher than the combined thickness of the fairing, hull,
backing block, and hull nut. This will ensure there is marine
sealant in the threads to seal the hull and hold the hull nut
securely in place.
Stainless steel transducer in a metal hull—To prevent
electrolytic corrosion, the stainless steel housing must be
isolated from the metal hull. Slide the isolation sleeve over the
bedded transducer stem as far down as possible (Figure 6).
Apply a 2mm (1/16") thick layer of the marine sealant to the
outside of the sleeve.
3. Apply a 2mm (1/16") thick layer of marine sealant to the
following surfaces:
• Fairing that will contact the hull
• Backing block that will contact the inside of the hull
• Hull nut that will contact the backing block
4. Thread the transducer cables through the fairing and seat the
transducer firmly within the recess. Be sure the arrow on the
transducer points toward the triangular recess in the fairing.
Installing the Transducer
1. From outside the hull, thread the transducer cables through the
mounting hole. Push the stem of the transducer (with the fairing
in place) into the mounting hole using a twisting motion to
squeeze out excess sealant (Figure 5 or 6). Be sure the arrow
on the transducer points forward toward the bow.
NOTE: The transducer must be FLUSH with the fairing. If it is
recessed more than 0.5mm (1/64") inside the fairing, you may
shim the transducer or carefully file/sand the fairing.
Stainless steel transducer in a metal hull—Be sure the
isolation sleeve is between the transducer stem and the hull
(Figure 6). However, the isolation sleeve must be below the
washer and hull nut to prevent the sleeve from interfering with
tightening the hull nut.
2. From inside the hull, slide the backing block onto the transducer
cables and stem, seating the backing block firmly against the
hull. Screw the hull nut in place, but do not tighten it at this time.
Bedding & Installing the Anti-rotation Bolt
CAUTION: Be sure the surfaces to be bedded are clean and dry.
1. Apply a 2mm (1/16") thick layer of marine sealant to the anti-
rotation bolt including the flange (Figure 5 or 6). The sealant
must be 6mm (1/4") higher than the combined thickness of the
fairing, hull, backing block, washer, and nut. This will ensure that
there is marine sealant on the threads to seal the hull and hold
the nut securely in place.
Figure 6. Bedding and installing in a metal hull
Copyright © 2017 Airmar Technology Corp.
BOW ►
NOTE: Be sure
the arrow on the
transducer
points forward
toward the bow.
anti-rotation
bolt
nut &
washer
triangular plug
backing
block
High-
surface facing
outward
hull
hull nut
stem
Performance
Fairing
with curved
SS542
marine sealant on following (shown in red):
- transducer, extending above hull nut 1/4" (NOT surface that will touch water)
- backing block that contacts hull
- hull nut that contacts backing block
- anti-rotation washer that contacts backing block
- yellow triangular plug: fill hollow half way (NOT curved surface that will touch water)
- anti-rotation bolt including bolt head, extending above nut 1/4"
- fairing that contacts hull
isolation sleeve
isolation sleeve

Stainless steel transducer in a metal hull—To prevent
electrolytic corrosion, the stainless steel anti-rotation bolt must
be isolated from the metal hull. Slide the isolation sleeve over the
bedded anti-rotation bolt as far down as possible (Figure 6).
Apply a 2mm (1/16") thick layer of the marine sealant to the
outside of the sleeve.
2. Apply a 2mm (1/16") thick layer of marine sealant to the side of
the washer that will contact the backing block.
3. Push the anti-rotation bolt through the fairing and the hull.
4. From inside the hull, screw the washer (sealant side down) and
the nut onto the anti-rotation bolt.
Stainless steel transducer in a metal hull—Be sure the
isolation sleeve is between the anti-rotation bolt and the hull
(Figure 6). However, the isolation sleeve must be below the
washer and nut to prevent the sleeve from interfering with
tightening the nut.
5. Use slip-joint pliers to tighten the hull nut. Then tighten the nut
on the anti-rotation bolt. Do not over-tighten, crushing the
fairing or hull.
Cored fiberglass hull—Do not over tighten, crushing the hull.
Wood hull—Allow for the wood to swell before tightening the nut.
6. Use marine sealant to half-fill the hollow in the yellow triangular
plug. Apply a 2mm (1/16") thick layer of marine sealant to the
three sides of the plug that form the triangle. The sealant will
hold the plug firmly within the fairing and fill any gap between
the anti-rotation bolt and the plug.
7. The yellow triangular plug fits one way only. Push the yellow
plug into the recess in the fairing until it is FLUSH with the
outside of the fairing. This will squeeze out excess sealant. If
necessary, tap it into place with a mallet.
NOTE: If the triangular plug is slightly recessed within the
fairing, use sealant to fill the gap. The plug must be FLUSH with
the fairing for good performance.
8. When the boat is underway, especially at high speeds, water
will enter any gaps and push against the fairing with
considerable force, possibly rotating it. Fill any gaps between
the fairing and the hull with marine sealant. If there is any gap
greater than 3mm (1/8"), replace the fairing. Remove the
excess sealant on the outside of the fairing and hull to ensure
smooth water flow under the transducer.
Cable Routing & Connecting
CAUTION: If the sensor came with a connector, do not remove it
to ease cable routing. If a cable must be cut and spliced, use
Airmar’s splash-proof Junction Box No. 33-035 and follow the
instructions supplied. Removing the waterproof connector or
cutting the cable, except when using a water-tight junction box,
will void the sensor warranty.
1. Route the cables to the instrument being careful not to tear the
cable jacket when passing it through the bulkhead(s) and other
parts of the boat. Use grommet(s) to prevent chafing. To reduce
electrical interference, separate the transducer cables from
other electrical wiring and the engine. Coil any excess cable and
secure it in place with cable ties to prevent damage.
2. Refer to the instrument owner’s manual to connect the
transducer to the instrument.
Checking for Leaks
When the boat is placed in the water, immediately check around the
transducer for leaks. Note that very small leaks may not be readily
observed. Do not leave the boat in the water for more than 3 hours
before checking it again. If there is a small leak, there may be
considerable bilge water accumulation after 24 hours. If a leak is
observed, repeat “Bedding” and “Installing” immediately (see page 4).
Installation in a Cored Fiberglass Hull
The core (wood or foam) must be cut and sealed carefully. The
core must be protected from water seepage, and the hull must be
reinforced to prevent it from crushing under the hull nut allowing
the transducer to become loose.
CAUTION: Completely seal the hull to prevent water seeping into
the core.
1. Drill a 3mm or 1/8" pilot hole perpendicular to the waterline from
inside the hull (Figure 7). If there is a rib, strut, or other hull
irregularity near the selected mounting location, drill from the
outside. If the hole is drilled in the wrong location, drill a second
hole in a better location. Apply masking tape to the outside of the
hull over the incorrect hole and fill it with epoxy.
2. Using the appropriate size drill bit or hole saw, cut a hole from
outside the hull through the outer skin only. Be sure to hold the
drill plumb, so the hole will be perpendicular to the water surface.
3. The optimal interior hole diameter is affected by the hull’s
thickness and deadrise angle. It must be large enough in
diameter to allow the core to be completely sealed.
Using the appropriate size drill bit or hole saw, cut through the
inner skin and most of the core from inside the hull keeping the
drill perpendicular to the hull. The core material can be very soft.
Apply only light pressure to the hole saw after cutting through the
inner skin to avoid accidentally cutting the outer skin.
4. Remove the plug of core material, so the inside of the outer skin
and the inner core of the hull is fully exposed. Sand and clean
the inner skin, core, and the outer skin around the hole.
5. Coat a hollow or solid cylinder of the correct diameter with wax
and tape it in place. Fill the gap between the cylinder and hull
with casting epoxy. After the epoxy has set, remove the cylinder.
6. Sand and clean the area around the hole, inside and outside, to
ensure that the sealant will adhere properly to the hull. If there
is any petroleum residue inside the hull, remove it with either
mild household detergent or a weak solvent, such as alcohol,
before sanding.
7. Follow the same procedure to prepare the hull for the anti-
rotation bolt. Repeat steps 1 through 6.
8. Proceed with the installation beginning with "Cutting the
Fairing" on page 3. Note that all holes are already drilled.
Anti-fouling Paint
Surfaces exposed to salt water must be coated with anti-fouling
paint. Use water-based anti-fouling paint only. Never use ketone-
based paint since ketones can attack many plastics possibly
damaging the transducer. Reapply anti-fouling paint every 6
months or at the beginning of each boating season.
hull’s outer skin to
hull
outer skin
solid or hollow
cylinder
pour in
casting
epoxy
core
inner skin
Figure 7. Preparing a cored fiberglass hull
Dimension equal to
the thickness of the
ensure adequate
clearance
Copyright © 2005 Airmar Technology Corp.
5

Maintenance, Parts & Replacement
Cleaning
Aquatic growth can accumulate rapidly on the transducer’s face
reducing its performance within weeks. Clean the surface with a
Scotch-Brite® scour pad and mild household detergent taking
care to avoid making scratches. If the fouling is severe, lightly wet
sand with fine grade wet/dry paper.
Replacement Transducer & Parts
The information needed to order a replacement transducer is
printed on the cable tag. Do not remove this tag. When ordering,
specify the part number, date, and frequency in kHz. For
convenient reference, record this information below.
Part No.________________Date___________Frequency_________kHz
Lost, broken, and worn parts should be replaced immediately.
Hull Nut NA
High-Performance Fairing NA
Please contact your Furuno dealer to obtain parts.
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